Ultra capacitors, sometimes referred to as super capacitors or double-layer capacitors, are capacitors with very high energy densities compared to that of conventional capacitors and very high power density compared to conventional lead acid batteries—refer to FIG. 1.
In recent years, motor vehicles have become fitted with more and more ancillary electrical devices, such as power windows, seating, satellite navigation, high powered audio systems, stability control and power steering. Some of these may be active or on call while the vehicle's engine is inoperative and the standard vehicle battery is not receiving a charge from the alternator. Some advanced luxury vehicles now require the installation of a heavy large battery in the luggage compartment to handle these extra power demands.
It is a disadvantage of conventional vehicle batteries that in some operating conditions there may then be insufficient capacity in the battery to effectively drive the vehicle's starter motor.
Another disadvantage of conventional vehicle batteries, typically lead acid batteries, is their loss of capacity in very low ambient temperatures. This is in contrast to ultra capacitors in which loss of capacity at comparative low temperatures is relatively insignificant.
There is a series of US patents assigned to Midtronics Inc including U.S. Pat. No. 7,015,674 which cover various aspects of booster packs based on capacitor storage technology for assisting the starting of a vehicle whose conventional battery has become depleted. Embodiments of the present application seek to provide a more efficient arrangement and, in some aspects, a system more suited for integration into modern, electronically controlled vehicles.
It is also the case that some vehicles now actually stop the internal combustion engine for short periods as a means of improving fuel efficiency. It is also the case that some vehicles now include electric motor assist whereby the internal combustion engine is stopped whilst the electric motor functions to propel the vehicle. The end result is an increased number of internal combustion engine start cycles putting additional pressure on conventional electrochemical battery-based arrangements for the starting of the vehicle's internal combustion engine.
It is an object of the present invention to address or at least ameliorate some of the above disadvantages or provide a useful alternative.